WASHINGTON -- Sidestepping controversy, House Majority Leader Eric Cantor, R-Va., declined to take sides Monday on a proposal for higher tax revenues backed by fellow Republicans on Congress' supercommittee, yet expressed confidence the panel would agree on a deficit-reduction plan of at least $1.2 trillion by a Nov. 23 deadline.

A proposal for $300 billion in higher taxes has stirred grumbling within the ranks of congressional Republicans, for whom opposition to such measures has been political bedrock for more than two decades.

Two of the party's presidential hopefuls said Monday they wouldn't support any committee deficit-reduction plan that includes higher taxes.

Former House Speaker Newt Gingrich, campaigning in Iowa, said he would "do everything in my power to defeat" any such proposal.

A spokesman for Rick Perry said the Texas governor "wants to look at details but if those details include a tax increase he's not going to be for it. He does not favor higher taxes," added David Miner.